1. Field
The present invention provides a rotational atherectomy device for removing a stenotic lesion from within a vessel of a patient. More specifically, the invention relates to a rotational atherectomy device for removing or reducing stenotic lesions in blood vessels such as a human artery by rotating an abrasive element within the vessel to partially or completely ablate the unwanted material.
2. Description of the Related Art
Atherosclerosis, the clogging of arteries, is a leading cause of coronary heart disease. Blood flow through the peripheral arteries (e.g., carotid, femoral, renal, etc.), is similarly affected by the development of atherosclerotic blockages. A conventional method of removing or reducing blockages in blood vessels is known as rotational atherectomy. A long guidewire is advanced into the diseased blood vessel and across the stenotic lesion. A hollow drive shaft is then advanced over the guidewire. The distal end of the drive shaft terminates in a burr provided with an abrasive surface formed from diamond grit or diamond particles. The burr is positioned against the occlusion and the drive shaft rotated at extremely high speeds (e.g., 20,000-160,000 rpm). As the burr rotates, the physician slowly advances it so that the abrasive surface of the burr scrapes against the occluding tissue and disintegrates it, reducing the occlusion and improving the blood flow through the vessel. Such a method and a device for performing the method are described in, for example, U.S. Pat. No. 4,990,134 to Auth.
It is also known from U.S. Pat. No. 6,132,444 to Shturman (the instant inventor) et al., to provide a drive shaft with an abrasive element eccentrically positioned proximally to and spaced away from the distal end of the drive shaft.
Rotational angioplasty (atherectomy) is frequently used to remove atherosclerotic or other blocking material from stenotic (blocked) coronary arteries and other blood vessels. However, a disadvantage with this technique is that abraded particles can migrate along the blood vessel distally and block very small diameter vessels including capillaries of the heart muscle itself. The effect of the particulate debris produced by this procedure is of major concern to physicians who practice in this field. Clearly, the existence of particulate matter in the blood stream is undesirable and can cause potentially life-threatening complications, especially if the particles are over a certain size.
Although the potentially detrimental effect caused by the presence of abraded particles in the blood vessels is reduced if they are very small microparticles, it is much more preferable to remove from the treated blood vessel any debris abraded or otherwise released from the stenotic lesion during treatment and thereby prevent migration of debris to other locations along the treated blood vessel.
A rotational atherectomy device, described in U.S. Pat. No. 5,681,336 (to Clement et al.), has been proposed which attempts to prevent migration of abraded particles along the blood stream by removing the ablated material from the blood vessel whilst the device is in use. The rotational atherectomy device known from U.S. Pat. No. 5,681,336 (to Clement et al.) has a complicated construction and is difficult to manufacture on a commercial scale.
A number of disadvantages associated with the known rotational atherectomy devices have been addressed in WO 2006/126076 to Shturman (the instant inventor). The present invention seeks to further improve rotational atherectomy devices known from this document and other disadvantages associated with known atherectomy devices.